PT-2025-8907 · Linux+9 · Linux Kernel+9

Dai Ngo · Published 2025-02-10 · Updated 2026-04-20 · CVE-2025-21795

Positive Technologies (AI Summary)

CVSS v3.1

5.5

Medium

Base vector

AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Name of the Vulnerable Software and Affected Versions Linux kernel (affected versions not specified)

Description A hang issue in the Linux kernel's NFSD has been resolved. The problem occurs when nfs4 client is in a courtesy state, causing nfsd4 shutdown callback to hang because cl cb inflight is not 0. This hang lasts approximately 15 minutes until TCP notifies NFSD that the connection was dropped. The issue is related to the nfsd4 run cb work function and the RPC call.

Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.

Exploit

Weakness Enumeration

CWE-99

Related Identifiers

ALSA-2025:20095

ALSA-2025:20518

BDU:2025-12319

CVE-2025-21795

DLA-4102-1

DLA-4178-1

INFSA-2025_20518

OESA-2025-1285

OESA-2025-1286

OPENSUSE-SU-2025_0847-1

OPENSUSE-SU-2025_0856-1

OPENSUSE-SU-2025_0955-1

RHSA-2025:20095

RHSA-2025:20518

RHSA-2025_20518

RHSA-2026:0804

SUSE-SU-2025:01919-1

SUSE-SU-2025:0847-1

SUSE-SU-2025:0856-1

SUSE-SU-2025:0955-1

SUSE-SU-2025:20190-1

SUSE-SU-2025:20192-1

SUSE-SU-2025:20260-1

SUSE-SU-2025:20270-1

SUSE-SU-2025_0847-1

SUSE-SU-2025_0856-1

SUSE-SU-2025_0955-1

USN-7510-1

USN-7510-2

USN-7510-3

USN-7510-4

USN-7510-5

USN-7510-6

USN-7510-7

USN-7510-8

USN-7511-1

USN-7511-2

USN-7511-3

USN-7512-1

USN-7521-1

USN-7521-2

USN-7521-3

USN-7593-1

USN-7602-1

USN-7703-1

USN-7703-2

USN-7703-3

USN-7703-4

USN-7719-1

USN-7737-1

Affected Products

Almalinux

Astra Linux

Debian

Linuxmint

Linux Kernel

Red Hat

Red Os

Rocky Linux

Suse

Ubuntu

References · 2043

• 🔥 https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/21xxx/CVE-2025-21795.json · Exploit
• https://osv.dev/vulnerability/USN-7510-4 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2024-53181 · Security Note
• https://ubuntu.com/security/CVE-2025-21864 · Vendor Advisory
• https://ubuntu.com/security/CVE-2025-21739 · Vendor Advisory
• https://ubuntu.com/security/CVE-2024-58080 · Vendor Advisory
• https://ubuntu.com/security/CVE-2025-23138 · Vendor Advisory
• https://ubuntu.com/security/CVE-2025-21852 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2024-56593 · Security Note
• https://ubuntu.com/security/CVE-2024-58002 · Vendor Advisory
• https://ubuntu.com/security/CVE-2025-21766 · Vendor Advisory
• https://osv.dev/vulnerability/SUSE-SU-2025:0856-1 · Vendor Advisory
• https://ubuntu.com/security/CVE-2025-21737 · Vendor Advisory
• https://ubuntu.com/security/CVE-2024-56608 · Vendor Advisory
• https://ubuntu.com/security/CVE-2025-21750 · Vendor Advisory